refactor: complete module-driven architecture migration

This commit completes the migration to a fully module-driven architecture:

## Models Migration
- Moved all domain models from models/database/ to their respective modules:
  - tenancy: User, Admin, Vendor, Company, Platform, VendorDomain, etc.
  - cms: MediaFile, VendorTheme
  - messaging: Email, VendorEmailSettings, VendorEmailTemplate
  - core: AdminMenuConfig
- models/database/ now only contains Base and TimestampMixin (infrastructure)

## Schemas Migration
- Moved all domain schemas from models/schema/ to their respective modules:
  - tenancy: company, vendor, admin, team, vendor_domain
  - cms: media, image, vendor_theme
  - messaging: email
- models/schema/ now only contains base.py and auth.py (infrastructure)

## Routes Migration
- Moved admin routes from app/api/v1/admin/ to modules:
  - menu_config.py -> core module
  - modules.py -> tenancy module
  - module_config.py -> tenancy module
- app/api/v1/admin/ now only aggregates auto-discovered module routes

## Menu System
- Implemented module-driven menu system with MenuDiscoveryService
- Extended FrontendType enum: PLATFORM, ADMIN, VENDOR, STOREFRONT
- Added MenuItemDefinition and MenuSectionDefinition dataclasses
- Each module now defines its own menu items in definition.py
- MenuService integrates with MenuDiscoveryService for template rendering

## Documentation
- Updated docs/architecture/models-structure.md
- Updated docs/architecture/menu-management.md
- Updated architecture validation rules for new exceptions

## Architecture Validation
- Updated MOD-019 rule to allow base.py in models/schema/
- Created core module exceptions.py and schemas/ directory
- All validation errors resolved (only warnings remain)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit/services/test_vendor_service.py

@@ -15,10 +15,10 @@ from app.modules.tenancy.exceptions import (
 from app.modules.marketplace.exceptions import MarketplaceProductNotFoundException
 from app.modules.catalog.exceptions import ProductAlreadyExistsException
 from app.modules.tenancy.services.vendor_service import VendorService
-from models.database.company import Company
-from models.database.vendor import Vendor
+from app.modules.tenancy.models import Company
+from app.modules.tenancy.models import Vendor
 from app.modules.catalog.schemas import ProductCreate
-from models.schema.vendor import VendorCreate
+from app.modules.tenancy.schemas.vendor import VendorCreate
 
 
 @pytest.fixture
@@ -582,7 +582,7 @@ class TestVendorServicePermissions:
 
     def test_can_update_vendor_non_owner(self, db, other_company, test_vendor):
         """Test non-owner cannot update vendor."""
-        from models.database.user import User
+        from app.modules.tenancy.models import User
 
         vendor = db.query(Vendor).filter(Vendor.id == test_vendor.id).first()
         other_user = db.query(User).filter(User.id == other_company.owner_user_id).first()
@@ -598,7 +598,7 @@ class TestVendorServicePermissions:
 
     def test_is_vendor_owner_false(self, db, other_company, test_vendor):
         """Test _is_vendor_owner returns False for non-owner."""
-        from models.database.user import User
+        from app.modules.tenancy.models import User
 
         vendor = db.query(Vendor).filter(Vendor.id == test_vendor.id).first()
         other_user = db.query(User).filter(User.id == other_company.owner_user_id).first()
@@ -643,7 +643,7 @@ class TestVendorServiceUpdate:
         from pydantic import BaseModel
 
         from app.modules.tenancy.exceptions import InsufficientPermissionsException
-        from models.database.user import User
+        from app.modules.tenancy.models import User
 
         class VendorUpdate(BaseModel):
             name: str | None = None
@@ -695,7 +695,7 @@ class TestVendorServiceUpdate:
     ):
         """Test marketplace settings update fails for unauthorized user."""
         from app.modules.tenancy.exceptions import InsufficientPermissionsException
-        from models.database.user import User
+        from app.modules.tenancy.models import User
 
         other_user = db.query(User).filter(User.id == other_company.owner_user_id).first()
         marketplace_config = {"letzshop_csv_url_fr": "https://example.com/fr.csv"}